At the Heart of the Abyss
Secondary attributes are things that generally don’t provide the basis for some kind of roll. Instead, they describe the character’s current condition, in relation to the best possible condition. How hurt the character is vrs fully healthy, current shield level, etc.
Other secondary attributes combine various factors to provide attributes for detailed situations. For instance, the Defense attribute is a combination of talent, training, and gear, all combined into a single number in order to streamline combat.
These attributes are generally set by the character’s class and to a lesser extent gear. They don’t get modified much at character creation except in response to the player’s primary attribute choices.
Secondary attributes will see the most fluctuation over the course of a single session, in contrast to primary Attributes that are fairly stable from session to session. Each attribute has it’s own page to explain it fully.